Integrating third party S function, folder structure and make files

I have been supplied a third party Sfunction, the folder structure is this:

When I place the model within IDD_Sfunc.slx into our model and try to generate code I get the following error:

Error in 'IDD_Sfunc/VscIdd/VscIdd_sfcn': Initialization commands cannot be evaluated.
Caused by:
Unable to find makefile: 
  C:\Users\Joseph.Holdsworth\Documents\Software\Keble\MATLAB\S3_VCM_Stage10b_R2015b\Main\Models\VCM\IDD\test_harness_template_1_S_Func_22Jan\VscIdd0_ert_rtw\VscIdd0.mk
for the generated MEX S-function 'VscIdd0_sf '.
This is required in order to show the underlying modules or to build a target from this model. If simulation capability is only needed, unselect the 'Show Module List' checkbox, otherwise try rebuilding the S-function target for model 'VscIdd0'

Its trying to find a make file in a folder that does not exist, what am I doing wrong?

Thanks